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Finding the Fourth Proportional to 81.13, 111.92 and 51.97

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Solution

The fourth proportional to 81.13, 111.92 and 51.97 is: 71.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.13 : 111.92 = 51.97 : x
  2. Step 2: Convert to fraction form
    81.13/111.92 = 51.97/x
  3. Step 3: Cross multiply
    81.13x = 111.92 × 51.97
  4. Step 4: Simplify right side
    81.13x = 5,816.22
  5. Step 5: Solve for x
    x = 5,816.22/81.13
  6. Step 6: Final answer
    x = 71.69

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.